This invention relates to an image processing apparatus, an image processing method, a program, and a storage medium for making easy the comparative reading of a plurality of images for medical use.
Up to now, a lot of radiation images such as X-ray images have been used in the diagnosis of disease etc., and for the purpose of obtaining these radiation images, what is called radiography, in which a fluorescent layer (fluorescent screen) is irradiated by X-rays transmitted through a radiographic object, the visible light which is produced by the irradiation is made to irradiate a film using silver halide in the same manner as a usual photographic film, and the irradiated film is developed, has been utilized very much for a long time.
On the other hand, in recent years, it has been put into practice to use a method of producing a radiation image without using a film coated with a silver halide layer, in which a radiation image is directly picked up as a digital signal from a radiation detector such as a stimulable phosphor detector or an FPD (Flat panel detector). Further, for the purpose of making a radiation image obtained by the above-mentioned method of producing a radiation image become an image suitable for diagnosis, it has been brought into practice to apply various kinds of image processing to digital image data.
Incidentally, as regards diagnosis based on the observation of the above-mentioned radiation image, the diagnosis is carried out, for example, with a plurality of films obtained for one and the same subject (radiation images of the chest region or the abdominal region taken once a year in the case of periodical health examination, radiation images for the observation in the course of recovery taken at the first medical examination and every several weeks in the case of a fracture of a bone, etc.) put side by side on a observation device to be compared with one another. However, in the case where the radiographs to be compared with one another are the combination of direct X-ray radiographs and indirect X-ray radiographs of one and the same subject, the combination of digital images read by a film scanner and digital images read from a stimulable phosphor detector, the combination of digital images read from a stimulable phosphor detector and digital images read through the conversion of X-ray energy into electric charge, or the like, caused by various factors, image characteristics such as the size of the whole of an image, the pixel size, the number of gray scales, the resolution, and the density (the luminance) become different between one image and another. For this reason, it sometimes occurred that the above-mentioned difference in the image characteristics became the obstacle of the exact comparative reading of images, which lowered the precision of diagnosis and the efficiency of diagnosis.
Therefore, for example, in the publication of the unexamined patent application H8-146540, it is disclosed a technology in which, by the correction of image data of a radiation image using supplementary image information concerning the radiographing conditions at the time of image data generation, the image characteristics are made equal between one and another of a plurality of images, and the difference in the image characteristics caused by the difference in the radiographing conditions etc. is corrected. Through this correction, it becomes possible to make the image characteristics equal between one and another of a plurality of images supposed to become the object of the comparative reading of images, and also it becomes possible to bring it out to the maximum, the effect of the extraction of diagnosis information based on the comparative reading of images and the correlation operation between images, and improve the precision of diagnosis and the efficiency of diagnosis.
However, as regards such a conventional image forming method, because the method is premised on the supplementary image information being attached to the radiographed image data, there have been cases where a radiation image taken in the past or a radiation image taken by an old-fashioned apparatus or an apparatus manufactured by another manufacturer had no supplementary image information attached or had deficient supplementary image information. For this reason, there has been a problem that correction processing for comparative reading of images could not be carried out, or the effect of correction processing was low even if correction could be made. As the result of this, there has been cases where a radiation image taken in the past or a radiation image taken by an apparatus of another model could not be utilized effectively, which lowered the precision of diagnosis and the efficiency of diagnosis.
It is an object of this invention to improve the precision of diagnosis and the efficiency of diagnosis by the correction of image data of an old radiation image taken under some other conditions or a radiation image taken by an apparatus of some other model to make comparative reading of images easy.
The structures to solve the above-mentioned problem are as follows:
(1) An image processing apparatus for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
an image data transforming means(device) for practicing image processing so as to make image characteristics of the target radiation images correspond to those of a radiation image for reference, on the basis of image characteristics obtained from said radiation image for reference determined beforehand.
In this specification, the term xe2x80x9cimage characteristicsxe2x80x9d is defined as those including, for example, the size of the whole of an image, the pixel size, the number of gray scales, the resolution, the density, the luminance, the gradation characteristic, the frequency response characteristic, etc.
(2) An image processing apparatus for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
an image characteristic obtaining means (device) for obtaining the image characteristics of a radiation image for reference and the image characteristics of the target radiation image, and
an image data transforming means (device) for practicing image processing of said target radiation image so as to make the image characteristics of said target radiation image correspond to the image characteristics of said radiation image for reference obtained by said image characteristic obtaining means.
Hence, by the image processing to make the image characteristics of a plurality of radiation images having different image characteristics correspond to those of a radiation image for reference, the difference in the image characteristics, for example, between radiation images taken under different radiographing conditions or radiation images subjected to different image processing methods can be dissolved, and it becomes possible to reproduce radiation images having their image characteristics made to correspond to one another.
(3) An image processing apparatus for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
a region recognizing means (device) for recognizing a specified region corresponding to a fixed structure of a radiographic object,
an image processing condition determining means (device) for obtaining the image characteristics through the analysis of the image signal of a specified region recognized by said region recognizing means, and determining the image processing conditions on the basis of said image characteristics, and
an image data transforming means (device) for practicing image processing of a radiation image on the basis of the image processing conditions determined by said image processing condition determining means,
said image processing condition determining means determining the image processing conditions on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference, or on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference and the image characteristics of a specified region to be obtained from the target radiation image, and
said image data transforming means practicing image processing of a part or the whole of the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.
Hence, by the practice of the image processing of the target radiation image on the basis of a specified region of a radiation image for reference, it becomes possible to reproduce a plurality of images with their image characteristics made to correspond to one another, and for example, even for a radiation image having no supplementary image information attached concerning the radiographing conditions and the image characteristics, image processing can be carried out so as to make its image characteristics correspond to the image characteristics of a radiation image for reference. Owing to this, in the case where a plurality of radiation images are subjected to comparative reading of images, it is possible to reproduce the region to be diagnosed with satisfactory image characteristics, and improve the precision of diagnosis and the efficiency of diagnosis. Further, by the practicing of image processing on the basis of the region supposed to be the object of diagnosis, an appropriate image processing can be carried out.
(4) An image processing apparatus for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
a region designating means (device) for recognizing a designated region as a specified region,
an image processing condition determining means (device) for obtaining the image characteristics through the analysis of the image signal of a specified region recognized by said region designating means, and determining the image processing conditions on the basis of said image characteristics, and
an image data transforming means (device) for practicing image processing of a radiation image on the basis of the image processing conditions determined by said image processing condition determining means,
said image processing condition determining means (device) determining the image processing conditions on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference, or on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference and the image characteristics of a specified region to be obtained from the target radiation image, and
said image data transforming means practicing image processing for a part or the whole of the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.
Hence, when image processing of the target radiation image is carried out so as to make its image characteristics correspond to the image characteristics of a radiation image for reference, a specified region of the radiation image for reference can be designated arbitrarily; therefore, in accordance with the state of the radiation image for reference, the image processing conditions can be determined with the optimum region used as the reference. Further, because it is possible to carry out an image processing of a high degree of freedom adapted to the preference of the diagnosis making person, the efficiency of diagnosis can be improved.
(5) An image processing apparatus as set forth in any one of the structures (1) to (4), characterized by the aforesaid radiation image for reference being generated on the basis of radiation transmitted through the same region of the same radiographic object as the aforesaid the target radiation image.
Hence, because it is possible to carry out image processing on the basis of a radiation image for reference with corresponding regions definitely specified in the radiation image for reference and the target radiation image, it is possible to reproduce a plurality of radiation images with uniform image characteristics. Further, for example, even for a radiation image which has undergone an image processing different from that of a radiation image for reference, if it is the one of the same region of the same radiographic object as that of the radiation image for reference, the difference in the image characteristics from the radiation image for reference can be recognized as the difference in the method of image processing, and the radiation image having undergone an image processing of a different method can be corrected to come to have an image characteristics close to the image characteristics of the image for reference. Owing to this, this invention can be applied to radiation images having diversified image characteristics, has a wide scope of application, and is good in facility.
(6) An image processing apparatus as set forth in the structure (3) or (4), characterized by
the aforesaid radiation image having supplementary image information showing the image characteristics attached, and
the aforesaid image processing condition determining means determining the image processing conditions on the basis of the image characteristics obtained from said supplementary image information, and the image characteristics obtained through the analysis of the image signal of the specified region recognized by the aforesaid region recognizing means or the aforesaid region designating means.
(7) An image processing apparatus as set forth in the structure (6), characterized by
the aforesaid supplementary image information including at least one or more of the size of the whole of an image, the pixel size, the number of gray scales, the resolution, the density, the luminance, the gradation characteristic, the condition of the irradiation by radiation, the characteristics of the radiation image conversion medium, and the condition of image reading.
Hence, in the case where supplementary image information showing the image characteristics is attached to a radiation image for reference and the target radiation image, the image processing conditions can be determined on the basis of not only the image characteristics obtained through the analysis of the image signal of the specified region obtained by the region recognizing means or the region designating means, but also the information such as the size of the image as a whole, the pixel size, the number of gray scales, the resolution, the density, the luminance, the gradation characteristic, the condition of the irradiation by radiation, the characteristics of the radiation image conversion medium, and the condition of image reading; therefore, the processing speed can be raised, and also an image processing of a high precision can be carried out.
(8) An image processing apparatus as set forth in any one of the structures (1) to (4), characterized by the aforesaid image processing including at least one of gradation processing, frequency processing, correction processing of pixel size, correction processing of the number of gray scales, compression processing of dynamic range, detection processing of an abnormal shade, position adjustment processing for correcting the positional deviation in the corresponding parts among a plurality of images, and frequency processing using a multiple resolution method.
Hence, for example, in the case where the radiation images are a plurality of time-serial images of one and the same region of one and the same radiographic object, the part changing with the passage of time can be selectively emphasized with a good precision by the practice of correction processing of the pixel size and the number of gray scales; owing to this, a change to a morbid state which has been newly generated, or a morbid part whose symptoms have varied can be easily detected. Further, by the practice of gradation processing, it is possible to correct the output density so as to make it of a constant density or of a constant contrast, on top of the gradation characteristic of the target radiation image having been made to correspond to that of a radiation for reference. Further, by the practicing of frequency processing, it becomes possible to prevent the sharpness of a radiation image being lowered and make the output of a stable image. Further, because gradation characteristic processing and frequency processing are practiced on top of the correction processing of the pixel size and the number of gray scales being carried out, it is possible to carry out an image processing of a higher precision. Besides, by the application of various kinds of image processing, it is possible to provide a high-quality radiation image.
(9) An image processing method for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
a process for carrying out image processing so as to make the target radiation image have image characteristics agreeing with the image characteristics of said radiation image for reference on the basis of the image characteristics of a radiation image for reference determined beforehand.
(10) An image processing method for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
a process for obtaining the image characteristics of a radiation image for reference and the image characteristics of the target radiation image, and
a process for carrying out image processing of said the target radiation image so as to make the target radiation image have image characteristics agreeing with the image characteristics of said radiation image for reference.
(11) An image processing method for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
a process for recognizing a specified region corresponding to a fixed structure of a radiographic object,
a process for obtaining the image characteristics of a radiation image for reference or of a radiation image for reference and the target radiation image through the analysis of the image signal obtained from a specified region of a radiation image for reference or of a radiation image for reference and the target radiation image, and determining the image processing conditions on the basis of the image characteristics of said radiation image for reference or of said radiation image for reference and said target radiation image, and
a process for practicing image processing for a part or the whole of the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.
(12) An image processing method for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by comprising
a process for recognizing a designated region as a specified region,
a process for obtaining the image characteristics of a radiation image for reference or of a radiation image for reference and the target radiation image through the analysis of the image signal obtained from a specified region of a radiation image for reference or of a radiation image for reference and the target radiation image, and determining the image processing conditions on the basis of the image characteristics of said radiation image for reference or of said radiation image for reference and said the target radiation image, and
a process for practicing image processing of a part or the whole of the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.
(13) A program for actualizing a function to make a computer for processing a target radiation image generated by radiation transmitted through a radiographic object practice image processing so as to make, on the basis of the image characteristics of a radiation image for reference determined beforehand, the image characteristics of the target radiation image correspond to the image characteristics of said radiation image for reference.
(14) A program for actualizing
a function to make a computer for processing a target radiation image generated by radiation transmitted through a radiographic object obtain the image characteristics of a radiation image for reference and the image characteristics of the target radiation image, and
a function to make said computer practice image processing so as to make the image characteristics of said target radiation image correspond to the image characteristics of said radiation image for reference.
(15) A program for actualizing
a function to make a computer for processing a target radiation image generated by radiation transmitted through a radiographic object recognize a specified region corresponding to a fixed structure of a radiographic object,
a function to make said computer obtain the image characteristics through the analysis of the image signal of said specified region recognized and determine the image processing conditions on the basis of said image characteristics,
a function to make said computer practice image processing of a radiation image on the basis of said image processing conditions determined,
a function to make said computer determine the image processing conditions on the basis of the image characteristics of a specified region to be obtained from said radiation image for reference, or on the basis of the image characteristics of a specified region to be obtained from said radiation image for reference and the image characteristics of a specified region to be obtained from the target radiation image, and
a function to make said computer practice image processing for a part or the whole of the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.
(16) A program for actualizing
a function to make a computer for processing a target radiation image generated by radiation transmitted through a radiographic object designate a specified region,
a function to make said computer obtain the image characteristics through the analysis of the image signal of said specified region designated and determine the image processing conditions on the basis of said image characteristics,
a function to make said computer practice image processing of a radiation image on the basis of said image processing conditions determined,
a function to make said computer determine the image processing conditions on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference, or on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference and the image characteristics of a specified region to be obtained from the target radiation image, and
a function to make said computer practice image processing for a part or the whole of said the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.
(17) A storage medium having a program stored capable of being practiced by a computer for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by
having a program stored including a program code capable of being practiced by a computer for practicing image processing so as to make, on the basis of the image characteristics of a radiation image for reference determined beforehand, the image characteristics of the target radiation image correspond to the image characteristics of said radiation image for reference.
(18) A storage medium having a program stored capable of being practiced by a computer for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by
having a program stored including
a program code for obtaining the image characteristics of a radiation image for reference and the image characteristics of the target radiation image, and
a program code capable of being practiced by a computer for practicing image processing so as to make said obtained image characteristics of said target radiation image correspond to said obtained image characteristics of said radiation image for reference.
(19) A storage medium having a program stored capable of being practiced by a computer for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by
having a program stored including
a program code capable of being practiced by a computer for recognizing a specified region corresponding to a fixed structure of a radiographic object
a program code capable of being practiced by a computer for obtaining the image characteristics of said specified region through the analysis of the image signal of said recognized specified region, and determining the image processing conditions on the basis of said image characteristics,
a program code capable of being practiced by a computer for practicing image processing of a radiation image on the basis of said image processing conditions determined,
a program code capable of being practiced by a computer for determining image processing conditions on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference, or on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference and the image characteristics of a specified region to be obtained from the target radiation image,
a program code capable of being practiced by a computer for practicing the image processing of a part or the whole of said the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.
(20) A storage medium having a program stored capable of being practiced by a computer for processing a target radiation image generated by radiation transmitted through a radiographic object, characterized by
having a program stored including
a program code capable of being practiced by a computer for designating a specified region
a program code capable of being practiced by a computer for obtaining the image characteristics of said specified region through the analysis of the image signal of said specified region designated, and determining the image processing conditions on the basis of said image characteristics,
a program code capable of being practiced by a computer for practicing image processing of a radiation image on the basis of said image processing conditions determined,
a program code capable of being practiced by a computer for determining image processing conditions on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference, or on the basis of the image characteristics of a specified region to be obtained from a radiation image for reference and the image characteristics of a specified region to be obtained from the target radiation image,
a program code capable of being practiced by a computer for practicing the image processing of a part or the whole of said the target radiation image in such a manner that the image characteristics of the target radiation image correspond to the image characteristics of a radiation image for reference on the basis of said image processing conditions.